export interface PersonProps{
  name:string;
  age:number;
  height:number;
  weight:number;
}

export interface StudentProps{
  book:string[]|string|null;
  grade:number;
}
export interface TeacherProps extends PersonProps{
  student: string | string[] | null;
  courseType: string;
}
export interface EmployeeProps{
  [index:number]:string;
}